‘This pattern was consistent, independent of the grouping or categorisation of behaviours.

‘On average, chimpanzee behavioural diversity was reduced by 88% when human impact was highest compared to locations with the least human impact.’

The researchers suggest that chimpanzee populations in areas with high human activity may be smaller, making it hard to pass on certain traits between generations.

Chimps on top of a termite nest (Getty Images)

The animals may stop displaying some behaviours to avoid attracting human attention and climate change could also be impacting behaviours, they said.

‘Our results suggest that chimpanzee populations are losing their characteristic sets of behavioural traits and that a number of not yet discovered behaviours may be lost without having ever been described,’ the authors wrote.

They suggest ‘chimpanzee cultural heritage sites’ are needed to protect these diverse sets of behaviours.

‘Specific interventions are needed to protect their natural resources and tool-use sites in order to maintain behavioural plasticity and safeguard their capacity for cultural evolution,’ the authors wrote.

The study, led by the Max Planck Institute for Evolutionary Anthropology and the German Centre for Integrative Biodiversity Research, has been published in the journal Science.